One of the most important parts of an internal combustion engine is its carburetor. Unless the carburetor performs well the engine will not start reliably, will not run smoothly and deliver adequate power and good gasoline mileage, and will produce excessive atmospheric pollutants.
Because the proper operation of the carburetion system is so essential to total engine performance, much attention has been given in the past to carburetor design and over the years the carburetor has become a complex device.
The complexity of the modern carburetor is apparent when it is recognized that the typical carburetor system employs six separate systems, i.e. a float system for controlling the level of fuel in the bowl; a low speed or idling system to provide an adequate fuel supply when air intake is low; a high speed or cruising system to overcome fuel inertia during a sudden increase in power demand; a power system to provide adequate fuel under conditions of reduced vacuum resulting from the opening of the throttle; and a choke system for increasing the fuel-to-air ratio under starting or low temperature conditions.
In addition, there are anti-percolation vents, hot idle compensators, anti-dieseling solenoids and deceleration controls in most modern carburetors.
This multitude of special systems and features requires careful adjustment and maintenance and the many small ducts and valves are vulnerable to blockage and wear by dust and dirt finding their way through the air filter.
Furthermore, until recently there has been a greater emphasis on certain aspects of performance such as starting, acceleration and power developed with insufficient emphasis given to gasoline mileage and atmospheric polluting conditions.
Thus, a need exists for a new approach to carburetion which will produce a better balance in total performance while utilizing a simpler design that does not require the numerous separate systems and special accessories and which provides in particular improved gas mileage and a lower level of atmospheric pollution.